1. Field of the Invention
The present invention concerns a lighting module for instruments with a liquid-crystal matrix. More particularly, it concerns a module comprising a casing including a back and lateral walls, the said matrix closing off the casing on its face opposite the back, and at least one fluorescent tube being disposed in the casing near the back.
2. Discussion of Related Art
The illumination of active or inactive liquid crystal matrix screens is generally provided by one or more fluorescent tubes with cold or hot cathodes according to the applications and the levels of luminance required. One of the drawbacks of these lighting devices lies in the power which they require, whilst one of the main advantages of active-matrix screens is precisely their very low consumption. This problem becomes crucial when these screens are used in instruments on the instrument panel of an aircraft where the light environments may reach very high levels. The power expended in the instruments to generate the level of light ensuring legibility of the screen under these conditions has an adverse effect on the reliability of the equipment.
Until now, the backs of the casings of known lighting modules were flat and white. Such an arrangement, however, has the drawback that a large part of the light is emitted in directions in which it is of no use, which is particularly the case in applications concerning an instrument panel, where the person required to take note of the information displayed by the instrument is sitting in a specific, precise position with respect to the screen.
The present invention aims to mitigate this drawback.